The loan system should be to promote development of youth players rather how it is sometimes used, as an overflow of senior pros because the club bought too many players.
http://www.chelseafc.com/on-loan-players
22 Chelsea players on loan. This means 22 players not available to their rivals.
I am in favour of loans for academy players but I think there should be some kind of rules about buying players and then sending them on loan to other teams. Ok Chelsea are not in ECL but potentially Essien helping Real Madrid beat rivals and then being unavailable for a RM-Chelsea is a bit iffy.